1. Field of the Invention
The present invention relates to wind turbines. More particularly, the present invention relates to wind turbine that have colors thereon so as to enhance the avian avoidance capability of such wind turbine. Additionally, the present invention relates to blades of wind turbines having colors formed thereon.
2. Description of Related Art
Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The development of windpower is source for the generation of electricity has led to the establishment of wind farms where multiple wind turbines are erected. Although wind turbines are environmentally safe, the wind turbines are reported to be hazardous to flying birds. The birds cannot effectively see the wind turbines when they are rotating. As such, they will fly into the moving turbines and can be maimed or killed.
Motion smear is the degradation of the visibility of rapidly moving objects that results in the inability of the retina of the eye to process the high temporal frequencies of stimulation that result from high velocities of retinal-image motion. In the case of wind turbines, motion smear occurs primarily at the tips of the blades. This makes them deceptively transparent at high-retinal image velocities. Attempts to minimize motion smear has taken to account its cause and attempts to reduce the temporal frequency of stimulation of the retina. Anti-motion smear patterns are designed to do this by not repeating the pattern in one location on a turbine blade at the same location on any other blade. In a three-blade turbine, the temporal frequency of stimulation is thereby reduced by a factor of three.
In birds, the rod and cone patterns of the retina are much greater than that in humans. As such, at nighttime, birds possess four to six times the ability of humans to distinguish color and to see objects. With wind turbine blades, the blades are typically canted at an angle with respect to the hub. As such, if the birds approaches the blades at an angle, it becomes very difficult to see the rotating blades.
Data has shown that anti-motion smear patterns produce a higher pattern electroretinogram amplitude from the retina. This translates into a higher pattern visibility at a given distance. For example, at a retinal velocity of 120° of visual angle/sec, the most effective anti-motion smear patterns produce pattern electroretinogram amplitudes that are three times the amplitude of the blade with no patterns. A single, solid black blade, when paired with two white blades, is one with the most visual stimulus because it may stimulate a larger area of the retina than striped blades. Even though these anti-motion smear patterns are more visible at a distance of approximately of 25 meters than blank blades or blades within unstaggered, repeating patterns, as the bird gets closer the blades, the retina is unable to process the progressively higher retinal-image velocities and all patterns rapidly lose visibility with decreasing distance.
U.S. Pat. No. 6,623,243, issued on Sep. 23, 2003 to W. Hodos, describes a method and apparatus for reducing avian collisions with wind turbines. A design or pattern is placed on the rotor blades of a wind turbine for reducing the motion smear of the image of the rotor blades on the bird's retina. When the motion smear on the bird's retina is reduced, the bird is capable of detecting the presence of the rotor blades more easily. This allows the bird to re-direct its flight path and avoid colliding with the wind turbine. In this patent, the design principle is that a pattern placed in a given location on one rotor blade is not repeated in the same location on any other rotor blades on the wind turbine. Although this provides an improved approach for avoiding avian collisions, ultimately, the patterns on the blades will tend to blend with one another so that the bird will perceive no difference between the separate colors. This arrangement provides no depth image to the bird and, as such, is not very effective at preventing collisions. In other words, as the blades rotate, a relatively smooth pattern ultimately develops as the blades spin rather rapidly. The bird will perceive not “chopping” between the separate blades and, as such, is not able to redirect its flight in the manner desired.
U.S. Pat. No. 6,945,752, issued on Sep. 20, 2005 to Wobben, describes a windpower generator in which the rotor blade includes a rotor blade connection and a rotor blade tip with a surface that is arranged therebetween. The surface is divided into at least two regions which differ with respect to lightness. The lighter regions are arranged closer to the rotor blade connection than the darker region. The darker region is of a natural shade and/or daylight sky shade.
U.S. Pat. No. 2,701,540, issued to Hamilton, describes the application of fluorescent paint to a propeller as integrated with a spiral stripe located on the propeller blade. The fluorescent material allows the blade to be more easily seen under nighttime conditions. The propeller is used in association with a bicycle.
U.S. Pat. No. 6,887,031, issued to Tocher, describes a habitat friendly wind energy generator. Large diameter concentrator wings capture and extract energy from a large area of the wind relative to the frontal area of the turbine shroud. At the same time, the wings presents a highly noticeable object to birds in flight. The concentrator wings are made more noticeable by the application of contrast in colors, shades or patterns made on these elements for installation of the embodiments of the wind energy generator within relatively featureless landscapes, such as prairies or deserts. The use of the markings and colorings also serves to improve the blending within other highly textured natural landscapes while minimizing hazards to birds in flight. It is desired that the wind turbines visually blend with the forest landscape.
U.S. Pat. No. 6,641,366, issued to Nordhoff, describes a windpower generating system with an obstruction lighting or night marking device. The blade includes insertion areas that have partial fiberoptical bundles integrated into their composite fiber material. These integrated partial optical fiber bundles result from an inner face arranged in the frontal area of the rotor blade. Light can be projected through these optical fiber bundles so as to allow the blade to be observed in nighttime conditions.
It is an object of the present invention to provide a blade for a wind turbine that serves to intensify color separation on the blades.
It is a further object of the present invention to provide a blade for a wind energy generator that enhances the red/blue color shift in the eyes of the birds.
It is a further object of the present invention to provide a blade for a wind turbine that enhances parallax with color, shape and movement.
It is a further object of the present invention to provide a blade for a wind energy generator that presents a chopping effect to the eyes of the bird.
It is still another object of the present invention to provide a blade for a wind turbine that can be observed by a bird flying at a sharp angle with respect to the blades.
It is sill another object of the present invention to provide a blade for a wind turbine that is easy to implement and relatively inexpensive.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.